Sludge remover



Feb. 13, 1934. D. w. TowNsEND AL v 1,947,429

SLUDGE REMOVER Filed Dec. 4. 192,9 S'Sheets-Sheet 2 ]d'elzzlolfsf @muri/Z Zd 701027567261,

Jam e5 Brame?? w/'d1 Feb. 13, .1934- D. w. TowNsEND Er AL 1,947,429

S LUDGE REMOVER Filed Dec. 4. 1929 l 5 Sheets-Sheet 5 lll .1MM QPatented Feb. 413, 1934` l i UNITED STATES PATENT OFFICE' SLUDGE REMOVERDarwin W. Townsend and James Brower, Milwaukee, Wis., assignors to ChainBelt Company, Milwaukee, Wis., a corporation of Wisconsin ApplicationDcccmbcr 4, 1929. serial Nc. 411,532

s claims. (ci. 21o-c55) The present invention relates to a method of agecontinuously without agitation thereof such and apparatus for theremoval of separable matas would cause its re-dissemination throughoutter which is being carried in suspension by a liqthe body of the liquid,with consequent saving in uid; and has for its object to improvesuchexpense and improvement and increase in the A method and apparatus inparticulars that will be claried eiiluent passed; such removal of the 60hereinafter particularly set out. The invention sludge from the liquidbeing accomplished in a has been devised with special reference to themore thorough manner, and the removed sludge treatment of city andindustrial sewage, and this being of greater density and 'with lessliquid voldescription will, therefore, be addressed to thel urne thanhas been attainable by any method or g) treatment, with increasede'iciency, of city sewapparatus heretofore known to us. 65

age by the now well knowny activated sludge Other objects and advantageswill be set forth method for the separation andrecovery of thehereinafter. v

solid materials thereof. According to the invention as herein disclosed,The invention will be the more easily appreciatliquid and the separablematter carried thereby ,5 ed and its importance understood if certainfacts are directed into a tank and separated therein. 70

incident to the activated sludge method of sew- The separated matter isthenrremoved at a uniage treatment be borne in mind. In practicing formrate from substantially every point on the such method the raw sewagehas introduced into bottom of the tank or on a plane parallel to the itcertain quantities of activated sludge obtainedsurface of the liquid.

o from already treated sewage in order to start and The invention isordinarily employed to remov 75 hasten the bacterial action upon whichthe sediment from liquids and is herein described as method depends.From this it follows that a cerapplied to the removal of sludge from4sewage, tain anlcuniy Varying accOlding t0 Circumstances, however, theinvention is not limited to that parbut always of considerable volume,of the sewageticular use,

c beine treated is re-handled, this necessitating in- The sewage isdirected into a tank or settling 80 creased equipment and expense Of.Operation basin in which the sludge is precipitated and from One of theobJects of the invention 1s to reduce which the Sludge is removed byhydrostatic presthe relative amount of the returned and re-han- Suredledsewage material, thus saving in equipment The inflow of Sewage and thedischarge of io and operating expense, besides effecting improvesludgeand claried liquid may be continuous so 85 ments in final resultsobtained, as will be later that the appaatus requires little attention.pomted out Y v The sludge is removed by a rotary sludge re- Another fact1S that actu/ated sludge m. occu' mover having a hollow hub connected tothe dislent State" a' product of the method bemg dls" charge outlet ofthe tank, collecting pipes extend- 90 55 missed-will settle quiterapidly if the liquid car- ;0 bed at the bottom'of the liquid where suchsetng`radi`ally from the hub and communicating ncccuicnt material be but1itt1c greater than that arranged along the conectmg plpes tlc cuect. e,

of the liquid itself and will collect in a mat or Sludge and dehver thes ame to the CO1 ec mg pipes as the sludge remover 1s rotated. 95

The collecting nozzles are so 4arranged that the sludge is collected atauniform rate from substantially every point on the bottom of the tankduring each revolution of the sludge retling is taking place, leavingthe liquid above, which passes off as the non-septic eluent, clear andpractically innocuous. But if such settled sludge deposit be stirred upor agitated and again i5 disseminated throughout the body of the liquid,A mover- 100 iti becomes dillicult and costly from a commercial Thesludge i5 Caued to flow into the collecting or practical point of viewto again cause precipinozzles by hydroslatlc pressure S0 that the raleOf.

tation thereof, but rather the sludge mixes with flOW and the denity 0fthe CollectedgfSl/udge may the ciment cf thc system, clouds the same andbe varied by varymg the rate 0f flOW 0f the Sew- 50 passes 01Ttherewith, and is apt to become septic, age iniO the tank and the lOW'Ofthe Sludge diS- 105 defeating the purpose of the sewage treatmentcharged thclefl'cmand causing the eiluent to become a menace and The lOW0f Sludge intO the collecting nOZZleS ldanger to public health. causesdown-currents in the sewage in the tank It is another purpose of thisinvention'to rewhich, greatly accelerate the precipitation of the `5move the settling sludge from the treated sewsludge and theprecipitation is further increased 110 by directing the sewage into thetank ina downward direction.

The down-currents in the sewage cause the sludge to be precipitated at asubstantially uniform rate over the entire area of the tank bottom.

Apparatus embodying the invention is shown in the accompanying drawingsin which the views are as follows:

Fig. 1 is a top plan view view.

Fig..2 is a vertical section on the line 2-2 of Fig. 1.

Fig. 3 is a vertical section on the line 3 3 of Fig. 1.

Fig. 4 is a central vertical section through the lower part of thesludge remover with parts thereof broken away.

Fig. 5 is a vertical section through the hub ofn the sludge remover,showing the same raised to permit the contents of the tank to flowdirectly into the discharge outlet.

Fig. 6 is a vertical section through mechanism for raising the sludgeremover.

The apparatus comprises, in general, a separating tank or settling basin1 in which the sewage is separated into sludge and clarified liquid, asupply conduit 2 to deliver sewage from its source to the tank 1,discharge conduits 3 and 4 to receive, respectively, claried liquid andsludge from the tank 1, and a rotary sludge remover 5 arranged in thetank 1 to remove the sludge therefrom and deliver the same to theconduit 4.

The supply conduit 2 delivers sewage to the tank 1 through inlets orports 6 which are inclined downwardly and provided with inlet valves 7to control the inflow of sewage.

The tank 1 has a sludge discharge outlet 8 arranged in the center of thebottom thereof and communicating with a discharge pipe 9 which leads toa sludge receptacle 10 arranged in the discharge conduit 4 and providedwith outlet valves 11 to control the discharge of sludge therefrom.

The level of the sewage in the tank, the rate of flow through the tank,the degree of separation, and the density of the precipitated sludge areall controlled by the valves 7 and 11.

The sewage in the tank l is maintained at a denite level so that theclarified liquid may overow into open troughs 12 which are carried byopposite side walls of the tank 1 and discharge into the conduit 3.

Scum or other oating matter is prevented from entering the troughs 12yby scum boards 13 arranged at the sides thereof and supported therebyso that, if the valves 7 and 11 are properly adjusted, the liquiddelivered to the conduit 3 is clear and free from foreign matter.

The precipitated sludge is collected by the sludge rremover 5 throughcollecting nozzles 14 which are arranged along collecting pipes 15extending radially from a hollow hub 16 and communicating with theinterior thereof.

The hollow hub 16 extends into the outlet 8 and is journaled in anannular bearing 17 which is carried by the bottom of the tank l andengages a shoulder 18 on the hub 16 to support the sludge remover.

The collecting pipes 15 may be supported also by braces 19 and 20 havingthe lower ends thereof secured to the pipes 1 5 and the upper endsthereof to a vertical shaft 21 which has one end connected to the hub 16and the other end journaled in a strut 22 arranged across the top hasbeen described has the collecting pipes 15 80 .arranged someconsiderable distance above the bottom or floor of the tank 1, while thenozzles 14 carried thereby extend downward, with their mouths or inletopenings located quite close to such floor. In a practical installationof the present invention, which has been in operation since 1929, thetank 1 is about fteen feet in depth, the pipes 15 are about`three feetabove the floor and the nozzles come to within about one inch or less ofthe floor surface. With such an arrangement the pipes 15are-substantially above the denser part of the bed of sludge whichcollects in the tank so they do not disturb it by their movements orcause the occulated particles thereof to be disseminated throughout thebody of liquid. And the nozzles are so disposed that they do not cause abreaking down of the bed of sludge until they are in position todirectly collect and confine it and directit to the pipes 15.

The sludge remover is rotated by an electric motor 23 which is carriedby the strut 22 and operatively connected to a gear or worm-wheel 24secured to a vertical shaft 21.

The nozzles 14 extend downwardly, outwardly and forwardly in thedirection of rotation of the sludge remover and are joined to the pipe15 at an oblique angle to reduce the resistance to the ow of sludgetherethrough.

The openings inthe nozzles 14 are large enough to collect the sludgewithout material agitation thereof before it is fully enclosed withinthe nozzles and they vary in size in accordance with the distance eachnozzle is spaced from the hub 16 as those nearer the outer ends of thecollecting pipes 15 traverse a greater area'of the tank bottom andcollect a greater amount of sludge than those nearer the hub 16.

The paths of the nozzles 14 carried by one pipe 15 do not coincide withthe paths of the nozzles carried by the adjacent pipes 15 so thatsubstantially every point on the bottomof th tank 1 is traversed by oneor more nozzles during each revolution of the sludge remover.

The sludge remover is rotated at slow speed to vpass the nozzles 14 overthe tank bottom so that the precipitated sludge is not agitated and, asthe sludge is collected in closed nozzles and pipes, the same is notdiffused into the claried liquid.

The precipitated sludge is collected while still 1&0 in suspension andthe pressure of the sewage in the tank causes the same to flow into thenozzles 14., through the collecting pipes 15, the hub 16, the'outlet 8,the discharge pipe 9, and the sludge receptacle 10 and past the valves11 to the discharge conduit 4 which carriesthe same away IIE@ and is soarranged that the level of the sludge therein is always below the levelof the sewage in the tank.

The ow of sludge into the collecting nozzles 14 causes downcurrents inthe sewage in the tank which assist in precipitating the sludge and alsoassist in causing the sludge to be precipitated evenly over the entirearea of the tank bottom.

.The vinlet ports 6 are arranged below the level of the liquid in thetank 1 andinclined downwardly to direct the incoming sewage toward thecenter of the tank bottom and prevent the same from polluting theclarified liquid at the top of the tank.

The density or concentration of the sludge is susceptible of closecontrol as the same may be varied by adjusting the valves '1 and 11 tovary the rate of ow through the tank or by regulating the speed of thesludge remover 5 to vary the rate of removal of sludge from the tankbottom. 4 r

'I'he density of the sludge blanket or bed,- which is largely determinedby the depth of the deposit, and this depth, in turn, by the intervalsbetween successive collections through the nozzles and pipes 15,-shouldbe, for reasons of economy and efficiency, as great as possible, bearingin mind the other factors of the process that must' be considered. It isrecognized by engineers skilled in the practice of the activated processof sewage treatmentthat a sludgev carrying from one and one half (l1/'2)to two (2) per cent solids is, for efficiency and economy, substantiallythe highest density or concentration obtainable in the settling tank.While sludge of this density is obtainable with the present day'settlingtank, the resultant sludge draw-off, prior to our invention, from tankshaving the aforesaid dense sludge, has been of less density (perhaps 'aslow as one per cent). This decrease in density of the sludge draw-olf,we believe to be caused by the non-uniform sludge withdrawal from thewhole area of the tank bottom, a defect which we correct by ourinvention.' With sludge of high livering ity into the incoming flowthereof, thanv is necessary when a less concentrated sludge is employed.And when it is remembered that from twenty to forty per cent. of theentire amount of sludge deposited is so returned, the saving effected byusing a dense sludge becomes apparent and indeed is an important factorin operation.

The sludge is ordinarily conductedby the conduit 4 to a treating orconversion plant but it may be diverted to a point of disposal through adrain pipe 25 which is connected to the dischargev pipe 9 and controlledby a normally closed drain valve 26.

By closing the inlet valves rI-and opening the drain valve 26, thecontents of the tank l may be drained to the level of the nozzles 141.

The entire mobile contents of the tank maybe drained by providingmechanism to raise the sludge remover 5 suiciently to uncover drainports 2'7 which are formed in theside wall of the hub 16 andnormallycovered by the bearing'l'l.

vThe drain ports 2'7 are shown uncovered in Fig. 5 and mechanism forraising the sludge remover to uncover the same is shown in Fig. 6.

The'lifting mechanism is carried by a support 28 which may be connectedto or form a part of the strut 22.

The support 28 has lifting screws 29 journaled u therein and supportinga bearing 30 which abuts a collar 31 arranged upon the shaft 21 andxedmove tlie sludge or settled iiocculated material, in order to bepractically successful, shall be of such character as not to stir up thesettled floccuiated substances but rather allow them to remain quiescentafter first settling and until the moment they are separated from thedeposited mass for removal.

Another feature lof great importance in the practcal treatment of sewageto separate and remove the sludge is that such removal shall becontinuous, that is capable of being carried on for long and indefiniteperiods of time during which precipitation of the sludge takes place;and that it shall be complete, that is to say, the removal of sludgemust be from the entire iloor surface of the tank or .receptacle whereinsedimentation is taking place, else portions ofthe deposit remainingunremoved, putrefaction therein. takes place with resulting foul odorsand/ or danger to health.

The method herein illustrated and described and the apparatus bywhich-it is carried out are such that the settled and collected sludgeis removed w-th little or no agitation of a nature that tends to causethe material constituting such sludge to be again disseminated throughthe body of liquid being treated for clarification and sludge removal.The process described is a continuous one, or one susceptible ofcontinuous operation. The arms 15 carrying the series of collectingnozzles 14 are sodeposited that the open ends or collecting mouths ofthe nozzles approach the bank of deposited sludge which is to be removedand take such material directly into the nozzles and the pipes or armsl5 without preliminary agitation of the mass. In this respect thecollector differs from prior apparatus of which we have knowledgewherein the'movements of the collecting arms or nozzles employedagitated the material by being moved over the top thereof or by beingdragged through the same preliminary to taking away the sludge from themass. By employing a series of hollow arms 15 carrying collectingnozzles 14 arranged as described, and moving these slowly andsuccessively over the floor of the tank in which the sewage or othermaterial is caused to settle, the sludge may be successfully andpractically removed from the whole surface of the tank bottom in auniform manner and without disturbing the quiescence of the settlingsludge preliminary to its entrance into the nozzles and ductsconstituting the collected and delivery means. By feeding the raw sewageor other liqu'd into the tank below the surface of the liquid thereinand from different sides and at widely separated'points as indicated inthe drawings, the flow of material from the entrance passages 6 to thedischarge openingsthrough the nozzles 14 is very uniform throughout theentire body of liquid within the tank, this being especially true wherea plurality of arms such as 15 are employed in the sludge collector.while there is a downward ow of liquid from the openings 6 to the mouthsor openings into the nozzles 14,v which flow tends to accelerate thedownward movement of the luocculatecl material for sedimentation, thereare nevertheless no decided currents established whichwould tend toagitate the settling material and keep it in sus pension.

ioo

By this arrangement,.

cations and adaptations within the scope of the appended claims.l

The invention is hereby claimed as follows:

l. A separator, comprising a tank wherein separation of sediment-bearingliquid into sludge and clarified liquid takes place, meansvto insure arelatively dense bed or layer of sludge being deposited uniformly uponthe bottom of the tank, and means operating in cycles for withdrawingthe accumulated sludge continuously and at a substantially uniform ratefrom the entire area of the tank bottom, without preliminary disturbancethereof tending to re-disseminate it throughout the body of the liquidin the tank,

during each complete cyclic operation thereof, the deposit of the sludgeand its removal, taking place simultaneously.

2. The combination, with a tank having an inlet for deliveringsediment-bearing liquid to said tank to be separated therein into sludgeand effluent, a discharge outlet for said effluent and a dischargeoutlet for said sludge, of a sludge remover rotatable about a verticalaxis and comprising a hollow hub 'communicating with said sludge outlet,a collecting pipe communicating' with said hub and extending radiallytherefrom, collecting nozzles arranged along said pipe and `carriedthereby, means to rotate said sludge remover and cause said sludge to becollected by said nozzles and delivered to said sludge outlet,

and means to drain the contents of said tank through said sludge outletindependently of said rotatable collecting sludge remover.

3. In a system for separating matter carried by liquid and capable ofseparation by sedimentation to form a sludge deposit; a tank whereinsedimentation takes place, a suction-acting col.- lector for Vtheremoval of the depositedfsludge, and means whereby the collector may berendered inoperative and the tank connected with an outlet for drainingthe tank independently of the saidsludge remover.

4. In a system for separating matter carried by liquid and capable ofseparation therefrom by sedimentation to form a' sludge deposit; a tankin which sedimentation takes place, a conduit leading therefrom throughwhich the sludge is car-- with inlets distributedl along the same fromthe inner to the outer ends thereof to remove said settled sedimentprogressively from concentric circular paths and deliver it through saidtubes to said outlet to be received direct from said tank in acontinuous flow, the inlets to the horizontal tubes of the sedimentremover being progressively larger in proportion to their distance fromthe axis about which they rotate.

6. The herein described method of treating sewage and similarsolid-carrying liquids, which consists in delivering the liquid into aprecipitating enclosure and allowing sludge to collect on the bottomthereof by gravity precipitation, leading off the clear liquid from theupper portion of the body of liquid and removing the sludge from thebottom of the enclosure by suction action carried' forwardsimultaneously along concentric circular paths, the removal beingprogressive and without substantial preliminary agitation of thesludge'and the amount of suction removal along any circular path beingproportional to the distance of that path from the axial center of theremoval operation.

7. The herein described method of treating sewage and similarsolid-carrying liquids, which consists in delivering such liquidv into aprecipitating enclosure and allowing sludge to collect on the bottomthereof by gravity precipitation, leading olf the clear liquid from theupper portion of the body of liquid, and collecting and removing thesludge,-the sludge collecting being by suction action carried onprogressively over the entire surface of the enclosure and withoutpreliminary agitation of the sludge, the suction taking the sludge fromthe side of the deposited mass thereof toward which the suction removalis advancing.

8. The method set forth in claim 7 further characterized by this, thatthe amount of suction-collection and removal along any circular'path isproportioned to the distance of that path from the axial center ofremoval, whereby the amount of removal per lineal unit; of advanceof thesuction along a circle nearer the center is the same as the amount ofcollection and removal per lineal unit of advance along a circular ypathfarther lecting tank, which consists of a series of hollow armsextending outwardly from and rotatable about a vertical axis, adapted tobe moved over the bottom of the tank and toward themass of material tobe removed, the arms being-provided respectively with a series ofentrance orifices which are open in a direction facing that in which thearms are moved toward the mass of sludge material to be taken awaythrough the orifices and arms the entranceforices to said arms beinglocated successively along the same and of graduated size, the openingsnearest the axis of rotation being smallest and successively graduallyincreasing in size toward the outer ends of the arms.

DARWIN W. TOW'NSEND.

JAMES BROWER.

